﻿using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Security.Cryptography;
using System.IO;

namespace Encryptor
{
    public static class EncryptService
    {
        const string KEY_64 = "RemoImag";//注意了，是8个字符，64位
        const string IV_64 = "RemoImag";
        public static string Encode(string data)
        {
            byte[] byKey = System.Text.ASCIIEncoding.ASCII.GetBytes(KEY_64);
            byte[] byIV = System.Text.ASCIIEncoding.ASCII.GetBytes(IV_64);

            DESCryptoServiceProvider cryptoProvider = new DESCryptoServiceProvider();
            int i = cryptoProvider.KeySize;
            MemoryStream ms = new MemoryStream();
            CryptoStream cst =
                new CryptoStream(
                    ms,
                    cryptoProvider.CreateEncryptor(byKey,
                                                   byIV),
                    CryptoStreamMode.Write);

            StreamWriter sw = new StreamWriter(cst);
            sw.Write(data);
            sw.Flush();
            cst.FlushFinalBlock();
            sw.Flush();
            return Convert.ToBase64String(ms.GetBuffer(), 0, (int)ms.Length);

        }

        public static string Decode(string data)
        {
            byte[] byKey = System.Text.ASCIIEncoding.ASCII.GetBytes(KEY_64);
            byte[] byIV = System.Text.ASCIIEncoding.ASCII.GetBytes(IV_64);

            byte[] byEnc;
            try
            {
                byEnc = Convert.FromBase64String(data);
            }
            catch
            {
                return null;
            }

            DESCryptoServiceProvider cryptoProvider = new DESCryptoServiceProvider();
            MemoryStream ms = new MemoryStream(byEnc);
            CryptoStream cst = new CryptoStream(
                ms,
                cryptoProvider.CreateDecryptor(byKey,
                                              byIV),
                CryptoStreamMode.Read);

            StreamReader sr = new StreamReader(cst);
            return sr.ReadToEnd();
        }
    }
}
